The evolution of inflators for automotive inflatable safety systems has resulted in the development of pressurized gas only inflators, propellant only inflators, and hybrid inflators. There are of course many design considerations for each of the above-noted types of inflators. In all three systems, two primary design considerations are that the air/safety bag must be expanded a predetermined amount in a predetermined amount of time in order to be operationally effective.
Since the weight of the automobile is an important design consideration in many instances today, so too then is the weight of the inflator. Moreover, due to the limited space available in many automotive designs, the size of the inflator is also an important design consideration.